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Network IQ export

Send live IQ to another analysis program over UDP or TCP.

Start an export

  1. Add Network IQ.
  2. Connect one Device IQ lane or one channel baseband output.
  3. Choose the protocol, sample encoding, and destination as host:port.
  4. Start the receiving program, then press Start export.
  5. Enter the displayed sample rate and centre frequency in the receiver.

A node accepts one source. Channel baseband exports filtered IQ at the channel's lower rate; each channel supports one export, independently of device-wide export.

Sample rate is locked during export. Retuning remains available, but you must update the receiving program's centre frequency. The display reports sent bytes, writes, capture overruns, and errors.

Wire contract

Payloads contain unframed, interleaved I, Q, I, Q, ... samples:

EncodingComponentsBytes per complex sampleGNU Radio input
cf32_leLittle-endian 32-bit float8Complex
ci16_leLittle-endian signed 16-bit integer4Short, then Interleaved Short to Complex
cu8Unsigned 8-bit integer, zero at 127.52RTL-SDR-style byte IQ

Encoding names follow SigMF datatypes. The stream carries no metadata, timestamps, or stream IDs.

UDP

Datagrams contain whole complex samples, with payloads up to 1,400 bytes. Configure GNU Radio's UDP Source with header None, matching data type, and payload size 1,400.

There are no sequence numbers. SDR-- reports loss before the socket but cannot detect missing or reordered network datagrams.

TCP

SDR-- connects to a listening receiver and writes a continuous byte stream. TCP preserves order and delivery, but a slow receiver can fill the bounded export queue. The export then stops and reports an error.

Access control

Exports can use substantial bandwidth and send to caller-selected destinations. Restrict server access to trusted operators with authentication and network controls.

Protocol compatibility

The output is raw IQ. Receiving software must accept the selected encoding and use the displayed rate and frequency. VITA 49 and DIFI framing are not supported.

rtl_tcp is a separate protocol for controlling remote radios. SDR-- supports it as a Device source.